The tetrameric streptavidin and avidin both have four sites that can specifically bind with biotin. Taking advantage of this high affinity binding, it is possible to realise multi-binding of biotinylated nanoparticles to avidin or streptavidin molecules. The iron oxide nanoparticles (IONPs) have been actively investigated in biomedical applications. In this work, biotinylated IONPs (biotin-IONPs) with around 10.5 nm magnetic core size were synthesised. They exhibited long-term hydrophilic stability, and the activity of the biotin content was verified by avidin-horseradish peroxidase induced chromogenic experiment. These biotin-IONPs were then studied as magnetic labels in substrate-based and substrate-free magnetic bio-labelling scheme of alpha-fetoprotein. The multi-binding ability of these biotin-IONPs with streptavidin functionalised detection antibody (streptavidin-detection antibody) was proved both on microplate well surfaces and in solution. Consequently, biotin-IONPs are promising magnetic label materials for the improvement of magnetic biodetection. In addition, the avidin-induced biotin-IONP assemblies were produced in MilliQ water solution and in water-in-oil microemulsion system. In summary, based on their multi-binding nature, the biotin-IONPs can be considered as a versatile material to improve the sensitivity of magnetic biodetection and to be further built into assemblies for future biomedical applications such as magnetic resonance imaging and target drug delivery.

The work reports on the exploitation of semi-sequential deep reactive ion etching (RIE) processes for realisation of deep vertically etched Si structures on Si substrate applicable in fibre-optic sensing systems. These processes employ different mixtures of gases including hexaflourosulphide, hydrogen and oxygen in a RIE system with a programmed passivation and etching sub-cycles. In the so-called semi-sequential processes, the intermediate purging steps are eliminated, which results in remaining little trace of reactant gases from the previous sub-cycle in the RIE machine's chamber, which can participate in the process of current sub-cycle. For the sake of minimum optical losses, which are accomplished by highly smooth vertical sidewalls, several etching processes were applied. In these processes, by controlling the etching parameters such as the flow of gases, plasma power and timing of each subsequence, the process can be controlled for minimum under-etch and surface roughness and maximum verticality of sidewalls. However, time and cost considerations should also be noted in the optimum fabrication process.

Visible and near-infrared light responsed Sn_1−x Bi _x S₂nanosheets was synthesised via a simple hydrothermal method. Rhodamine B was adopted to evaluate the degradation efficiency of the as-prepared samples. Experimental results showed that the doping content of Bi³⁺ could obviously affect the degradation efficiency of SnS₂. It was first increased and then decreased with increasing the Bi³⁺ content under the visible light irradiation. When the mole fraction of doping Bi³⁺ was 5%, the as-prepared Sn_0.95Bi_0.05S₂ with a bandgap of 0.38 eV had the highest degradation efficiency of 95.9% in 120 min. Moreover, the as-prepared composites possessed more effective electron–hole pair separation than that of pure SnS₂. In addition, a possible degradation mechanism of the as-prepared Sn_0.95Bi_0.05S₂ was proposed.

Altering the composition of layered double hydroxides (LDHs) is an effective method for changing their properties. In this study, LDH films with different compositions were fabricated on conductive cloth by using a hydrothermal method. Electron microscopy, X-ray diffraction, and UV–vis diffuse reflectance spectroscopy were used to investigate the morphology, crystal structure, and optical properties of the LDH films. The photocatalytic activity of LDHs with different compositions in the degradation of methyl orange was investigated under visible light irradiation. Our experimental results show that the reductive sites (Ni(II) and Co(II)) of LDHs and the conductive substrate improve the separation of photogenerated charges and prevent the particle aggregation of LDHs. LDH films (NiAl-LDHs, NiFe-LDHs, and CoAl-LDHs) with reductive sites (Ni(II) and Co(II)) exhibit higher visible light photocatalytic performance.

Microbial contamination poses a serious threat to human health. The evaluation of alternative systems and their reliability for the treatment of water is essential. In this work, a new method for the deposit of more silver nanoparticles (AgNPs) on the external surface of nanoparticles is presented. nanoparticles were synthesised by chemical co-precipitation and were modified in two stages using 3-mercaptopropyl trimethoxysilane and grafting allyl glycidyl ether and N, N-dimethylacrylamide. Then, AgNPs were loaded onto the modified to be used for water disinfection. The resulting nanoparticles were characterised by transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometer and thermal gravimetric analysis. Batch experiments were performed to investigate the effects of parameters such as amount of , contact time, and initial concentrations of MPN (the most probable number) and pH. The kinetic data was analysed by pseudo-first-order and pseudo-second-order equations. Results showed that the optimum conditions were a contact time of 30 min (94%), 50 mg of , and a pH was 6.5 for the maximum MPN removal efficiency (99.76%) in 750 cfu/ml MPN. On the basis of the results of fitting data, the pseudo-second-order kinetic model was selected as suitable for the data.

For the first time, a modified Schottky barrier carbon nanotube field-effect transistor (SB-CNTFET) with lightly doped drain (LDD) has been proposed. The newly designed CNTFET benefits from the advantages of both SB in source and the lightly doped ohmic drain contact. Simulations are based on two-dimensional non-equilibrium Green's function solved self-consistently with Poisson's equation. To get to an improved electrical characteristic, comparisons have been made among four CNTFET structures which are conventional SB-CNTFETs, triple LDD-CNTFET (TLDD-CNTFET), double LDD-CNTFET and Schottky source and ohmic drain CNTFET. The results show that the TLDD-CNTFET design decreases the leakage current significantly and increases on–off-current ratio as well as the cut-off frequency. It is also demonstrated that TLDD-CNTFET structure possesses three perceivable steps in the potential profile of the channel, which leads to additional lateral electric field peaks inside the channel and thus improve the immunity against short-channel effects. The important parameters such as transconductance, on–off ratio, subthreshold swing, cut-off frequency, delay and drain-induced barrier lowering of the CNTFETs have been calculated and discussed. Results show that by using lightly doped regions in the drain of SB-CNTFETs, the dc and ac characteristics have been considerably improved compared with the conventional SB-CNTFET.

The objective of the present work is the comparison of two common milling methods for the production of complex metallic alloy nanoparticles. γ-Al₁₂Mg₁₇ nanoparticles were fabricated using both a planetary ball mill and a SPEX mill. The produced nanoparticles have been compared on the basis of the phase and microstructural characterisations by means of X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The crystallite size, lattice strain, and lattice parameter have been calculated from the XRD data followed by an investigation on the powder morphology and particle size by FESEM. It has been indicated that the higher milling speed in the SPEX milling method leads to a higher milling energy and consequently lower particle size. For the same milling time of 2 h, the particle size decreases down to nano-scale using a SPEX ball mill whereas the planetary ball mill products contained a varied size in the range of micron and submicron regimes. Furthermore, the results showed approximate crystalline sizes of 12 and 85 nm for the Al₁₂Mg₁₇ in SPEX and planetary ball mills after 2 h of milling time, respectively.

The fabrication complexity and cost effectiveness in nanoscale regime have been one of the major issues in the modern biosensor. Therefore, to overcome such issue, this study investigates a junctionless dielectrically modulated electrically doped tunnel field effect transistor (FET) as a biosensor for application of label free detection. In this work, the authors have been considered the heavily doped silicon layer and two isolate gates for the formation of intrinsic and source regions underneath the control gate (CG) and polarity gate (PG) with appropriate work functions and polarity bias over silicon body which are similar to that of conventional tunnel FET. The proposed device structure is immune against doping control issues, avoids thermal budget, and fabrication issues. Moreover, the formation of nanogap cavity embedded within the CG dielectric is performed by etching of CG dielectric region towards the PG side for the purpose of sensing the biomolecules. The sensing ability of the proposed device has been evaluated in terms of varying the dielectric constant and charge density of the biomolecules. However, transfer characteristics are also evaluated with the variation in thickness and length of the cavity. All the simulations have been performed using ATLAS technology computer aided design device simulator.

A prompt γ neutron activation analysis (PGNAA) facility based on a ²⁵²Cf spontaneous fission neutron was performed with the final goal of obtaining various optimised radiation protection design parameters. MCNP Monte Carlo code was used to simulate the lead (Pb) shield thickness on two sides of the sample chamber, and B₄C, B₂O₃, LiOH, LiF, and borax were selected as neutron-absorbing materials that were simulated to determine optimal parameters for the optimal design of a biological multilayer composite shield. A series of calculations performed with the MCNP code indicated that the 5 cm thick Pb innermost layer of a biological shield rapidly reduced fast neutrons, and a moderation layer of 25 cm thick paraffin, 20 mm thick borax, and 2 mm thick B₄C were selected as neutron-absorbing materials. The calculated biological shield protection parameters satisfied the requirements of the PGNAA facility used in the experiment.

Mechanical properties of nanoporous silver have been investigated by nanoindentation. Experiment shows that the hardness and elastic modulus are both involved with strong surface size effect. Under the same loading rate, hardness decreases from 56.7 to 26 MPa along with indentation depth increasing from 200 to 2000 nm, while the corresponding elastic modulus increases from 2.68 to 3.73 GPa. In the case of the same indentation depth, the hardness decreases from 53 to 7.4 MPa with ligament size increasing from 100 to 198 nm, and the corresponding elastic modulus reduces from 4.7 to 0.17 GPa. The calculated indentation size effect index m is 0.34, revealing that nanoporous silver has a good ductility in micro-state, but brittle in the macro-state.

This work reports a complementary metal-SU8-graphene (MSG) method for constructing integrated graphene nanocircuits with excellent air and temperature stability. In this approach, electron beam (e-beam) lithography was first used to selectively pattern micro/nanoscale meshes on pristine graphene to form p-type regions. Then SU-8 thin films were spun and e-beam patterned to convert the target region of p-type graphene into n-type. The SU-8 was utilised as a doping source and an encapsulating layer for n-type graphene. To demonstrate the proposed MSG method, a graphene-based voltage inverter is constructed by complementary doping p- and n-type field effect transistors on a single graphene sheet. The electronic and thermal characteristics of the fabricated device were also studied.

The superhydrophobic surface of aluminium alloy was fabricated by nanosecond laser facility. The surface structures of the specimen were observed by scanning electron microscope and confocal laser scanning microscope. Surface hydrophobicity was evaluated by contact angle of deionised water. The phases present in the aluminium alloy surface were identified by X-ray energy spectrum analysis module of scanning electron microscope. The study showed that, a simple method of the fabrication of superhydrophobic aluminium alloy surface by twice nanosecond laser scanning, can make bowl like micro-nano structure on the surface of specimen. Compared with the contact angle of 140.21 degrees, which of sample surface with groove structure obtained by using once nanosecond laser scanning, the contact angle of the sample surface prepared by twice nanosecond laser scanning can up to 154.36 degrees. On the as-obtained sample surface, there is the hydrophobic substance containing more oxygen element, because of the coupling effect of laser and material. The surface roughness is related to the depth of the microstructure, and has no clear relationship with the surface wettability. Therefore, it is speculated that the joint action micro-nano structure and hydrophobic elements made the surface of aluminium alloy show super hydrophobicity.

This work develops an extended Stöber method to obtain SiO₂@polydopamine with a one-pot process. Such composites can be further processed to obtain hollow N-doped carbon capsules (HNCSs). More importantly, the HNCSs can be used as templates to synthesise HNCSs@Fe₃O₄ and HNCSs@MnO₂ composites, which greatly widened the application of HNCSs.

Bi₂S₃ nanorods were prepared by a facile in-situ thermal sulphuration method using BiOCl nanosheets as precursors. The products were characterised by X-ray diffraction, Raman scattering, Fourier-transform infrared spectroscopy and scanning electron microscopy. The optical properties were measured by ultraviolet-visible spectroscopy and photoluminescence techniques. The photosensitive properties were investigated by the photoelectrochemical method. The Bi₂S₃ sample was of pure orthorhombic phase and composed of nanorods with average diameter of ∼200 nm and length of ∼2 μm. A plausible gas phase growth mechanism was proposed which involved the partly templating of the shape of precursors by transforming BiOCl nanosheets to Bi₂S₃nanorods. The photocurrent of the products under irradiation of solar simulator reached 1.0 μA/cm² without bias voltage which was ten times that of the dark current. The photoelectric measurements clearly demonstrate that the as-prepared Bi₂S₃ nanorods possess excellent photosensitivity with stability and reproducibility, enabling the products suitable for the fabrication of high-performance photodetectors and other optoelectric devices.

A simple and low-cost method is proposed to measure the etching rate of monocrystalline silicon in KOH solution with various pHs through atomic force microscopy. The native oxide on the silicon surface is applied as a mask film to achieve selective etching. A quadrate-part area of the native oxide on silicon substrate surface is removed through the non-destructive tribochemical removal of the SiO₂ microsphere. As a result, the fresh subsurface silicon is exposed and etched smoothly. The adjacent remaining native oxide is hardly etched by the KOH solution. After etching in KOH, a step forms at the boundary between the remaining native oxide layer and exposed silicon surface. The atomistic-precision measurement of atomic force microscopy can detect a tiny etching depth of silicon, thereby acquiring the accurate etching rate in the KOH solution. This method provides a new and simple concept to measure the etching rate of materials in a suitable etchant and afford high-precision measurement to the etching rate required in the design of a material etching process.

In this work, the effects of halides on the properties of mixed-halide perovskite films are investigated. The films were prepared by sequential deposition two-step technique. PbI₂ or PbI₂-PbCl₂ solution was first spin-coated on fluorine-doped tin oxide glasses, and CH₃NH₃(I _x Br _y ) solution, with different molar ratio of I⁻ and Br⁻ (1:0, 2:1, 4:1, 1:4, 1:2, and 0:1), was subsequently coated on top. Then, the films were annealed at 90°C for 1 h and 100°C for 25 min to transform into perovskite structure. The characterisation of perovskite films included X-ray diffraction, ultraviolet–visible spectroscopy, photoluminescence spectroscopy, and scanning electron microscopy. The results indicated that the incorporation of Br⁻ and/or Cl⁻ in iodine-based perovskites, i.e. CH₃NH₃Pb(I_1−x Br _x )₃ and CH₃NH₃Pb(I_1−x−y Br _x Cl _y )₃, would enlarge their bandgap. However, with the use of PbI₂ precursor, excess PbI₂ occurred and resulted in minor affects on the structural and optical properties. The use of PbCl₂ as chlorine source was also found to affect the quality of the film morphology. The analysis in this study could provide another insightful aspect for understanding the role of halides in the synthesis of mixed-halide perovskites.

Based on Hamilton's principle and the modified couple stress theory, a Bernoulli–Euler microbeam model is developed with the finite rotation of the cross-section. The present model includes three couple-stress-induced nonlinear terms, and these nonlinear terms have a significant influence on the mechanic response of the beam.

Preparation of silver nanocubes (Ag NCs) with low temperature and controlled shapes is challenging in an aqueous solution because of its anticipated low embodied energy and experiment controllability. In this work, Ag NCs have been successfully synthesised under facile reaction conditions (at 30°C oil bath and under daylight illumination) by coordination effects of thermal reduction and photoinduced reduction. The obtained Ag NCs were characterised by transmission electron microscopy, UV–visible spectrophotometer and X-ray diffractometer. It turned out that, Ag NCs were prepared by using trifluoroacetic acid silver, cetyltrimethyl ammonium chloride, ascorbic acid, ferric chloride and sodium hydrosulphide as raw materials, and their sizes around 35 nm. Besides, as-synthesised Ag NCs with uniform size and high yield would serve as outstanding substrates for surface-enhanced Raman scattering detection, and as sacrificial templates to fabricate Au nanocages.

Noble metal nanostructures serve as excellent substrates for the detection of trace amounts of substances in surface enhanced Raman spectroscopy, but they have not found widespread commercial use due to their instability and short shelf lives. This work demonstrates that silver nanoparticles grown onto substrates with nanoscale roughness, using glancing angle physical vapour deposition and subsequently thermally annealed at 500°C to generate a stable lower energy configuration, exhibit Raman enhancements that are strong and remain stable with no drop over 30 days. These nanoparticle arrays may serve as time stable substrates for commercial scale Raman spectroscopy or may be employed in harsh environments.

BiFe_{1− x} Ni _x O₃ (x = 0%, 1, 2 and 3%) films were deposited on ITO/glass substrate using sol–gel process. The work reports the impacts of Ni doped on the crystal microstructure, leakage current, conduction mechanism and ferroelectric behaviour systematically. From the XRD analysis, all samples match well with the perovskite structure without impurity phase. Polarisation-electric filed hysteresis loop demonstrates that the optimal Ni-doped content of BiFeO₃ films is x = 2%, of which the remnant double polarisation (2P _r) is 141.4 μC/cm² at the test electric field of 1067 kV/cm. Leakage current density curves show that Ni doping has a great contribution in reducing leakage. The value of leakage is 4.79 × 10⁻⁷ A/cm² at tested electric field of 300 kV/cm. In addition, the leakage conduction mechanism transforms from the Ohmic conduction under the low electric field into the space charge limited conduction under high electric field. Ni doped does not cause significant change in the conduction mechanism.

Two different deposition sequences were carried to investigate ZnS and indium-tin oxide (ITO) multiple thin films on quartz substrates using magnetron sputtering technique. In the deposition order of ITO on ZnS layer, ZnS acts as a buffer layer with a thickness of at least 10 nm, and ITO thin film has (222) preferential orientation growth. Besides, lattice constant expansion phenomenon was observed when the film thickness of ITO was increased, indicating tension stress increase in ITO film. The lattice constant mismatch of 5% is the reason for the preferential orientation growth between ZnS and ITO thin films. In the other deposition sequence of ZnS on ITO layer, ZnS thin film has (111) preferential orientation growth. While ITO was kept in multiple crystalline properties. Pinhole-free ZnS thin film was observed by scanning electron microscopy for this deposition sequential, promising well interface in the thin film solar cells with lower interface defects.

In this work, a mathematical modelling of M-ary Poisson reception processes in molecular communication (MC) environment is performed. A lower bound of the capacity of MC system is derived using maxentropic capacity-approaching distributions; and the variation of the capacity with distance, drift velocity, and diffusion coefficient is analytically studied. Average symbol error probability (ASEP) of the considered system is analysed using maximum likelihood (ML) detection criterion. In order to improve on the error performance, an ML sequence detector employing hard decision Viterbi decoding is proposed. The proposed detection allows for a significant improvement in ASEP with some increase in system complexity.

The Ti³⁺ self-doped titanium dioxide (TiO₂) nanosheets with co-exposed {001} and {101} facets were successfully synthesised by the one-step solvent thermal method. The as-prepared samples were characterised by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy. The results showed that the Ti³⁺ self-doped TiO₂ nanosheets with anatase structure exposed {001} and {101} facets. XPS spectra confirmed Ti³⁺ were self-doped TiO₂ nanosheets, and which narrowed the band gap of TiO₂. Comparing to bare TiO₂, the Ti³⁺ self-doped TiO₂ nanosheets exhibited excellent photocatalytic activities. The reasons were that the co-exposed {001} and {101} crystalline facet effectively improved the separation efficiency of photogenerated electron–hole pairs, and the existence of Ti³⁺ and oxygen vacancy resulted in a narrowing band gap and enhancing visible absorption.

Polydopamine-functionalised graphene–Fe₃O₄–Ag composites (PGFA) were fabricated using a facile method. The morphology, structure, and chemical components of PGFA are investigated using various techniques, including X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. PGFA exhibits high catalytic activity for the degradation of p-nitrophenol. Furthermore, PGFA presents excellent catalytic stability and can be reused successfully for 14 cycles, maintaining high degradation efficiency (>98%). Antibacterial tests show that PGFA offers significant antibacterial potential against E. coli and S. aureus.

This work presents the experimental and statistical characterisation of carbon nanofibres (CNFs) dispersed in acetone. The purpose of the work is to study the process-induced properties in CNF aqueous dispersion. Dispersing techniques such as sonication and high shear-speed mixing were provided to disperse the CNFs. Response surface methodology was used here to design experiments and predict the nanoparticle size distribution after the dispersion. The effect of dispersing techniques and CNF concentration on nanofibre dispersion in acetone was investigated by quantitative and qualitative methods.

A facile and one-pot method using NaCl/KCl as a molten salt medium was developed to tune the porous structure of N,S-doped carbon derived from biomass at high temperature. With increasing the NaCl/KCl amount, the structures of the obtained carbons revealed by scanning electron microscopy become more and more open. N₂ adsorption/desorption isotherm shows that the hierarchical porous structure could be efficiently tuned by adjusting the amount of NaCl/KCl salt mixture. Specific surface area (SSA) of as-prepared N,S-doped carbon could reach 1478.6 m² g⁻¹. The relative ratio of micropore/mesopore drops with the increased NaCl/KCl. When the obtained carbons are used as the catalysts for oxygen reduction reaction (ORR), high catalytic activities are obtained, which result from the porous structure and doping effect of N atoms. Meanwhile, a volcano trend of the electrochemical performance for as-prepared carbons is also shown, which is a result of multiple factors possessing the opposite effect on ORR. Importantly, producing N,S-doped carbon from egg white in NaCl/KCl molten salt medium could provide a promising approach to synthesise the opened N,S-doped carbons with a controllably porous structure and large SSA based on biomass precursors.

The authors have studied the formation of an interfused network of nanofibres in multiple-needle electrospinning, a phenomenon reported here for the first time to their knowledge. Their study points to the significant role of humidity in controlling the morphology of nanofibre ensemble in electrospinning: when the humidity is sufficiently low, entangled mat of nanofibres with little or no interfusion between them are formed. However, at sufficiently high humidity, electrospun jets diffused into each other, forming a network of interfused fibres. The onset of jet interfusion during electrospinning is notable with naked eyes. The humidity that corresponds to the onset of the jet interfusion is referred to as the humidity threshold. They studied the formation of the nanofibre interfusion, and the relationships between humidity threshold and nanofibre diameters with processing parameters. They then presented a theory which explains the formation of the interfused network of fibres in terms of water condensation on the jets due to evaporative cooling. The presented approach allows for direct (one-step) fabrication of high surface area interfused nanofibre network without post-processing. This unique fibre structure can have significant implications on fibre applications for air and water filtering, where the structural integrity of the filter matters.

A heterogeneous nanocomposite (NC) of g-C₃N₄/W₁₈O₄₉ based on the coupling of W₁₈O₄₉ nanorods (NRs) with the graphitic carbon nitride (g-C₃N₄) sheets has been synthesised via a solvothermal method. The as-synthesised products were characterised by X-ray diffraction, X-ray photoelectron spectrometry, and transmission electron microscopy. The g-C₃N₄/W₁₈O₄₉ NC exhibited very strong adsorption ability towards the methylene blue (MB) dye and demonstrated a high removal efficiency of 99.14% after 0.5 h equilibration in dark. Compared to the g-C₃N₄ sheets and W₁₈O₄₉ NRs, the g-C₃N₄/W₁₈O₄₉ NC exhibited higher removal efficiencies towards both the MB and methyl orange (MO) dyes via a combination of adsorption and degradation. The photocatalytic process of the g-C₃N₄/W₁₈O₄₉ NC followed the Z-scheme photocatalytic mechanism. This work provides an efficient strategy for the synthesis of g-C₃N₄-based heterogeneous photocatalysts.

Mineral graphite has been effectively used to produce high quality graphene sheets, and a promising top-down approach for the production of graphene from graphite is liquid-phase exfoliation (LPF) because of its versatility and intrinsic ease of operation. Here, the work introduces a novel method for LPF, and they present preliminary results on the effects of ultrasonication assisted LPF of graphite in liquid nitrogen (cryo-ultrasonication at 77 K), comparing it with untreated graphite and graphite exfoliated by ultrasonication in distilled water at room temperature (∼300 K). Atomic force microscopy was employed to investigate and to assess at the nanoscale the effect of the cryo-ultrasonication on the exfoliation of the graphite surface. Various graphene single-layers with an area of >0.2 μm² were obtained after cryo-ultrasonication in liquid nitrogen working at 40 kHz, 100 W for 10 min. The present investigation demonstrates that graphene single-layers can be easily produced by ultrasonication assisted LPF of graphite immersed in liquid nitrogen.

Euryale ferox shells were used to prepare activated carbon (AC) by physiochemical activation using potassium hydroxide as the activation agent at 800°C for 2 h. The as-prepared AC surface area was 2028 m² g⁻¹, while the average pore diameter and total pore volume were 3.425 nm and 0.98 cm³ g⁻¹, respectively. The equilibrium and kinetics for the adsorption of methylene blue (MB) on E. ferox shell-based AC were investigated at 20°C. The equilibrium data for MB adsorption were in agreement with Langmuir equation, and the maximum adsorption value was 617 mg g⁻¹. Adsorption was denoted by two simplified kinetic models, pseudo-first-order and pseudo-second-order equations, respectively. The MB adsorption was well fitted to the pseudo-second-order model. Thermodynamics parameters were calculated and discussed and the adsorption of MB on E. ferox shell-based AC was exothermic and spontaneous.

This study is dealing with optimisation of the green synthesised silver nanoparticles (AgNPs) using the Taguchi design. Orthogonal array of L₉ type was used as an experimental design to detect the optimum conditions for synthesis of AgNPs. AgNPs were synthesised using the extract of Mentha longifolia as a reducing agent. In addition to the colour changes, ultraviolet visible spectroscopy was used to attest the appearance of AgNPs. Meanwhile, yielded AgNPs were characterised by FT-IR, scanning electron microscopy and dynamic light scattering (DLS) technique. UV–visible spectrophotometer showed absorbance peak at 340 nm. DLS analysis showed that the synthesised AgNPs are 21.1 nm in optimum conditions. The optimised condition for the synthesis of AgNPs revealed that silver nitrate concentration was 10 mM, temperature was 60°C, pH was 9 and plant extract concentration was 3%. The results demonstrated that AgNPs can be synthesised by controlling silver nitrate and plant extract concentration, pH and temperature. The minimum diameter predicted by statistical model was 35 nm while the obtained diameter was 21.1 nm which is very close to the experimental designed measure. This indicates that the statistical predicated proposed by Taguchi was correct.

In this work, calcium deficient hydroxyapatites (HAPs) [Ca_10−x (PO₄)₆(OH)₂] [where x = 0 − 0.3] were synthesised by precipitation method and calcined samples were characterised by Fourier transformation infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy techniques to check phase purity, calcium deficiency, particle size and shape. The results indicate that the structure of the HAP can tolerate a calcium deficiency up to 0.2. The calcium deficient HAP (x = 0.1) powder was found to be highly porous with a particle size below 200 nm. This powder was used as a drug delivery carrier for the drug, ciprofloxacin and sustained release of the drug in the phosphate buffer solution was investigated.

Zinc oxide (ZnO) microstructures were successfully prepared by hydrothermal synthesis with PEG4000 at 120°C for 24 h. The crystalline phase and morphology of ZnO microstructures were characterised by X-ray diffraction and scanning electron microscopy. The results show that the rod-like, flower-like and dumbbell-shaped ZnO microstructures can be easily controlled by varying the amount of PEG4000. The photoluminescence spectra of ZnO microstructures with different morphology at room temperature show four emission peaks at about 362, 389, 421 and 487 nm. The photocatalytic activities of ZnO microstructures are evaluated by degradation of methylene blue (MB) under ultraviolet light irradiation, and the degradation rates of MB with rod-like, flower-like and dumbbell-shaped ZnO microstructures reached 94.8, 95.4 and 70.9%, respectively.

This work introduces a structure of GaN FinFET at the nanoscale (channel length L = 5 nm) and characterises its performance in low power circuit applications. The simulated outcomes justify its application in circuits having , , and of the order of , , and , respectively, with quality factor Q = 1.11 × 10⁻⁵ S-dec/mV computed at and V _DS = 0.5 V. The measured observations are compared with other materials and we observed significant improvement, of the orders of 1 in the case of and 3 in the case of ; while the same for the Q witnesses a growth of 42%, especially with respect to silicon. The prospect of the proposed device architecture has also been investigated by implementing it in the digital circuits such as the inverter and universal logic gates (NAND and NOR gates), where it showed improved performance like high gain and absence of overshoot and undershoot in the switching characteristics.

The inactivation of lipases caused by organic solvents, high temperature, extremely acidic and alkaline requires a high stability. In this work, a novel one-pot synthesis for the lipase immobilisation on silica nanoparticles was reported. The optimal amounts of (3-ammonia propyl) triethoxysilane (APTES) and ammonia were studied. The apparent K _m value of the immobilised Candida rugosa lipase (CRL) was lower than that of free enzyme, showing affinity of the immobilised CRL to its substrate had increased. The results of stability test showed that the immobilised lipase was more stable than free enzyme at different temperatures and pH values. In particular, the immobilised CRL kept 96% activity at 90°C, while the free enzyme only remained 75% activity. Immobilised lipase had high catalytic efficiency, enhanced stability and recyclable usability compared to free enzymes, because of the cross-linking between the protein and the rigid carrier. Therefore, the immobilised method would be beneficial to improving the activity and stability of enzyme universally.